Major Meteor Showers

Adapted from the book,
What's Out Tonight?
Celestial Almanac & Astronomy Field Guide,
2000 to 2050
by Ken Graun

Peak Date**
 Hourly Count***
 QUADRANTIDS****  Bootes  Jan 3  60 - 200
 LYRIDS  Lyra  Apr 22  15 - 20+
 Eta AQUARIDS  Aquarius  May 5  60
 Delta AQUARIDS  Aquarius  Jul 29  20
 PERSEIDS  Perseus  Aug 12  120 - 160
 ORIONIDS  Orion  Oct 21  20
 TAURIDS  Taurus  Nov 5 -13  5
 LEONIDS  Leo  Nov 17  10*****
 GEMINIDS  Gemini  Dec 14  120
 URSIDS  Ursa Minor  Dec 22  10+

*Showers have traditionally been named after the constellation they appear to radiate from. **Peak date is approximate and may vary by a day from year to year. ***Hourly count is frequency or number of meteors per hour around the Peak date. ****The Quadrantids was named after an obsolete constellation recognized in the 1800s. Today, this shower is sometimes referred to as the Bootids, after the constellation Bootes. *****This shower has the potential to become a meteor storm, with spectacular displays of thousands of meteors per hour.



Observing Meteors & Showers

Meteors are observed best with the naked eye. It is not practical to view them with binoculars or a telescope because they last just a fraction of a second and extend arcs greater than what can be viewed through these instruments. Additionally, their appearance and paths in the sky cannot be predicted.

The first time you see a meteor, you will probably say, "What was that?" Unless you are looking in the direction of the meteor, you will either miss it or catch it out of the corner of your eye.

Meteors not associated with showers are called sporadic meteors. Both sporadic meteors and shower meteors can appear anywhere in the sky. Although the shower meteors originate from a point in the sky, this will not be immediately apparent when you watch showers. So, you do not have to look a any particular spot in the sky to observe meteor showers. Just look up, or better yet, lay in a lawn chair. To reiterate, meteors come from small particles in the path of the Earth's orbit and not from the stars in the constellations.

The most favorable time to observe meteors or showers is from around midnight to early morning (3 am or so) when the night side of the Earth is moving toward the meteoroids. And, the viewing is best when the Moon is not out.



A Meteor Primer

On a typical clear night, while looking at the sky, you will probably see a meteor, commonly called a shooting star. In fact, about seven meteors per hour can be seen normally. But at specific times of the year, there are meteor showers which may allow you to see 15 to 100 meteors per hour. On very rare occasions, if you are fortunate, you may encounter a storm with thousands of meteors per hour.

Meteoroid, Meteor and Meteorite
These terms are often confused. A meteoroid is a small rock in space. When a meteoroid enters the Earth's atmosphere, we view it as a white luminous streak called a meteor. If the meteoroid survives its journey through the atmosphere and happens to reach the Earth's surface as a "rock," it is then called a meteorite.

Meteoroid "Small rock in space (or grain of sand)
Meteor "White luminous streak seen in sky
Meteorite "Space rock" on ground

Size, Speed & Height
Most meteors are caused by meteoroids the size of a grain of sand. Atmospheric speeds reach up to 45 miles per second or 162,000 miles per hour (72 km/sec or 257,500 km/hr) and their trail height ranges from 30 to 60 miles (48 to 96 km) above the Earth's surface.

The Bright Ones
A very bright meteor, about the brightness of Venus, is called a fireball. An exceedingly bright meteor, much brighter than a fireball, is called a bolide. If you see a bright meteor, you will not easily forget it. I still remember the first one I saw when I was growing up, riding my bicycle home one night in Milwaukee.

Meteor Showers
Meteor showers are caused by the sand-size silicate particles left behind by comets. A dozen meteor showers occur every year as the Earth passes through semi-permanent fields of cometary debris that also orbit the Sun.

Meteors associated with showers appear to originate from a spot in the sky. A shower is named after the constellation from which the meteors appears to originate.

New showers will be established as future cometary debris crosses Earth's orbit. Existing showers will eventually fade away as debris dissipates. The Perseids have been around for a thousand years, while there is no indication of the Quadrantids further back than 200 years.

Shower intensity varies and cannot be predicted accurately from year to year. Some forecasts are available in the popular monthly astronomy magazines.

Meteor Storms
I have never experienced a meteor storm. The last reported storm was associated with the Leonids in 1966. For a period of about an hour, more than a hundred thousand meteors pierced the sky. To say the least, watching meteors rain down, filling the entire sky would be awesome!

The Draconids (a small shower that peaks on October 8th) and Leonids are currently the only known showers capable of storms. Storms result when the Earth hits pockets of concentrated silicate particles. The debris from future comets may also produce such displays.

Adopted from the book, Whats Out Tonight? Celestial Almanac & Astronomy Field Guide, 2000 to 2050 by Ken Graun. Copyright ©2007 by Ken Graun.